Use it

label end_of_chapter1:
    if not scfg.owns("chapter2"):
        "Chapter 2 is available for 4.99 USDC."
        $ result = scfg.pay("unlock", item="chapter2")

    if scfg.owns("chapter2"):
        jump chapter2
    "Maybe later, then."

Tips (the player can change the suggested amount on the payment screen):

$ result = scfg.pay("tip", amount="3.00", token="USDC")

Buttons in screens use non-blocking actions:

textbutton "Support the developer" action ScfgPay("tip", amount="3", token="USDC")
textbutton "Restore purchases" action CryptoRestore()

Every call and the PaymentResult fields are listed in the API reference.

Callbacks

init python:
    def on_payment(result):
        if result.status == "paid":
            achievement.grant("supporter")
    scfg.on_result = on_payment          # also catches payments finished after a restart

    # per call:
    # $ scfg.pay("unlock", item="chapter2", callback=on_payment)

Rules:

Callbacks run on the main thread, for side effects only. Never call jump, call or renpy.call_screen inside one; change the story using pay()'s return value or owns().
The receipt is saved before your callback runs. Ownership never depends on the callback.
A session can report "cancelled" or "expired" and later "paid" (the player paid late). Always treat "paid" as final.

Callbacks​

Callbacks